(1) Field of the Invention.
The invention relates to a blocking element, particularly for a gate used as a checkpoint, which comprises two circle-sector-like blocking vanes which are mounted, by way of their narrow sector inner side and such that they can pivot about a horizontally directed pivot axis, on a support which is arranged in the housing and in response to a signal, in a manner driven by a drive motor, can slide one over the other or one into the other in a fan-like or telescopic manner from a position which blocks the passage, in order to open the passage, and can be drawn apart from one another in order to again block the passage.
(2) Description of Related Art including information disclosed under 37 CFR 1.97 and 1.98.
Known blocking elements for so-called turnstiles used as checkpoints, for example as disclosed by DE patent 28 25 787 or DE 44 45 698 C2, are blocking units which can be rotated about a rotary axis which is inclined downward through approximately 45° and preferably have three blocking arms which are inclined in relation to the rotary axis and of which in each case one is in a position which is substantially horizontal and blocks the passage in the operating position of the turnstile. An unlockable blocking mechanism can be used to allow the blocking unit to rotate in response to a signal, this rotation being restricted such that the blocking arm which is initially in the blocking position moves out of this position and the following blocking arm assumes the blocking position, with the passage being temporarily opened for one person. It has been found in various turnstiles of this type that, on account of the comparatively fast rotation which said turnstiles must execute, a high impact force is produced and there is therefore a risk of injury, primarily to children who, on account of their small body size, may be struck in the upper region of the body or even the head by the following rotating blocking arm. In addition, this type of blocking unit takes up a relatively large amount of space.
Blocking barriers or barrier bars which can be pivoted horizontally or vertically through 90° are known primarily in gates for motor vehicles, but, when of correspondingly smaller design, have also previously been used for pedestrian gates. The impact force in the respective end position of the barrier also constitutes a problem in barriers of this type, all the more so when quick release and, subsequently, similarly quick renewed blocking of the path is required; in this case, it is necessary to provide measures for damping movement at the end of each pivoting movement, in order to prevent damage. The risk of injury is not precluded here either. In addition, a correspondingly large amount of space is likewise required on account of the pivoting movement of the barrier bar through 90°.
FR 2 849 519 and www.automaticsystems.com disclose a gate in which a circle-sector-like blocking element is pivoted out of a housing, which restricts the passage on one side, in response to a signal and thus blocks the passage. This blocking element is articulated approximately halfway up the housing. The result of this is that, whereas the upper region of passage can be blocked relatively well, a large gap through which the gate can be easily bypassed from below remains open in the lower region. Restrictions are placed on the size of this blocking element on account of the desired compact construction and even more so on account of the required stability.
www.automaticsystems.com likewise discloses a gate whose blocking element comprises two circle-sector-like blocking vanes which can slide one into the other in a telescopic manner and together into a lateral housing in order to open the passage. To this end, one, outer blocking vane is formed from two walls with a cavity in which said blocking vane can accommodate the other, inner blocking vane. The outer blocking vane can be pivoted about a pivot axis close to the floor; the inner blocking vane can be pivoted about a higher pivot axis. Although the passage is already blocked more effectively than in the case of the gate according to FR 2 849 519 as a result, the higher pivot axis of the inner blocking vane means that a gap which can be bypassed from below still remains open. The two blocking vanes have a guide groove which follows the sector arc and with which the outer blocking vane can be guided into the housing and the inner blocking vane can be guided into the outer blocking vane during their pivoting movement. In the process, the blocking vanes are subjected to continuous abrasive wear in these guide grooves and traces of this abrasive wear can already be seen from the outside after an extremely short period of operation.
Gunnebo Entrance Control AB discloses a gate with two blocking vanes which can slide one into the other in a telescopic manner. One, outer blocking vane is driven about a deeper-lying pivot axis to its pivot position by an electric motor via a lever mechanism. An upright metal plate which has a tooth system at its free end is provided in the housing. A semicircular gear wheel which is connected to the outer blocking vane and is mounted on the higher drive shaft of the other, inner blocking vane engages with this tooth system. When the outer blocking vane is pivoted about its pivot axis in a manner driven by the motor, the gear wheel rolls on the tooth system of the stationary metal plate and in the process carries along the inner blocking vane, so that said inner blocking vane is moved out of the outer blocking vane. The gear mechanism is very complicated and therefore relatively expensive, and at the same time susceptible to faults and not functionally reliable. It is subject to continuous abrasive wear and produces disturbing noise, particularly when, for cost reasons, a relatively crude tooth system is selected.
The object of the invention is to provide a blocking element of the type mentioned in the introduction which permits a space-saving and also lightweight construction, with which the passage can be blocked as far as possible over the full height of the gate housing, that is to say unauthorized passage through the gate is precluded, and with which the danger of injury can be largely avoided. In spite of the desired lightweight, compact construction, the required stability must be ensured in every case. The drive should be as simple and cost-effective as possible in terms of design, be subject to little wear and run smoothly.